真空预压软基处理沉降监测分析

FIELD TEST ANALYSIS OF THE SETTLEMENTS OF SOFT SOILS TREATED WITH VACUUM DRAINAGE PRELOADING IN COASTAL REGION OF TIANJIN

在天津滨海新区某真空预压处理现场进行了地面沉降和分层沉降监测,地面沉降总量80～160mm左右,由工前沉降和施工沉降组成;分层沉降监测资料揭示了沉降量主要产生在吹填土和海相沉积软弱地层中,而且埋设分层沉降观测设施在软弱地层形成的扰动带,会产生难以避免的误差。由于塑料排水带的存在,增加了真空预压场地中软土的渗透性,通过理论推导和具体算例,提出了利用沉降观测资料计算土体固结度需考虑其瞬时沉降,建议计算采用地基处理手册相关公式为宜。

This paper presents and analzes the monitored results of the surface settlement, subsection - settlements at a soft soil ground treated with vacuum drainage preloading in the coastal region of Tianjin. The total surface settlements reached about 80 to 160 mm. They were composed of the construction settlement and the pre - construction settlement. By subsection -settlement monitoring, the main settlement happened in the dredged fill and marine soft soil. The disturbed soil which produced by construction induced the avoidable errors of the subsection - settlement. With drainage strips, the characters of soils were changed. Through theoretic deduction and practical calculation on the soil consolidation degree, the results suggest that the correlative way in the foundation treatment manu should be adopted and the immediate settlement should not be ignored. At the site of the vacuum drainage preloading, the special character of the soft soil and its influence on the construction of excavation, pile foundtion etc should be investigated further more.